The present invention relates generally to method and apparatus concerning the removal of water moisture from a gas and, in particular, to method and apparatus concerning the removal of water moisture from ambient air prior to the ambient air being applied at a gas turbine system.
The removal of water moisture from gases, including the removal of finely divided water droplets suspended in air for example and referred to herein as an air/water mist, is performed in a variety of circumstances. One such circumstance, for example, concerns the operation of a gas turbine system for generating electricity in which an ambient air stream is mixed with fuel and the mixture combusted to produce gaseous products of combustion that are employed to drive a turbine that powers a rotor of an electric generator. Typically in such an operation, the ambient air that is mixed with the fuel can first be subjected to certain conditioning procedures.
As an example of the foregoing, the ambient air can be filtered to remove particulate matter that can damage the turbine equipment and the air can be cooled to become more dense. The denser air provides a higher mass flow rate and pressure ratio at the gas turbine equipment, resulting in an increase in turbine output and efficiency. In certain instances in which the air is filtered so as to remove particulate matter, water moisture that can be present in the air can be deposited at the filters. The water moisture deposited in this way at the filters can combine with the solid particulate matter also deposited at the filters forming a coating on the filters that interferes with the free flow of the air through the filters. As a result, an increased pressure loss can be experienced at the filters. Thus, it can be advantageous to remove the water moisture from the air stream delivered to the filters and subsequently applied at the gas turbine system.
One technique for removing the water moisture from an air stream involves the use of inertial separators or drift eliminators that force the air stream to pass along a tortuous pathway that causes the particles of water moisture to drop out of the air stream. This technique is best suited for particles of water moisture that are larger than the droplets of water that are present in an air/water mist. Another technique involves the use of so-called coalescing filters. In this technique, an air stream containing the particles of water moisture is caused to pass through a network of coalescing filters with which the particles of water moisture collide, thereby dropping out of the air stream. In addition, the particles of water moisture can collide with one another and, as a result, drop out of the air stream.